Once upon a time, there was a fisherman lived in a North Sumatra. Don’t ask me the year, all I know it was a very long time before you were born. When he was fishing in a river, a big fish was nailed. This fish had gold color all over its body. It was beautiful. The fisherman was very excited. He imagined a delicious dinner in his head. He put the fish in his basket and went home happily.

When he got home, he put the fish in a sink. He grabbed a knife to kill the fish. But when he almost killed it, he saw the fish eyes and felt pity. He took the knife away and put the fish in washbasin and added water in it. “Don’t worry, I wouldn’t kill you” the fisherman said.

The fisherman went fishing again. But this time he couldn’t get any fish. He went home with nothing in his hand. His stomach started to sing. He walked home slouching. He was surprised when he saw smoke came out from his kitchen.

“Who cooked in my kitchen?” he confused.

He took a peep and surprised when he saw a beautiful girl cooked in his house. “Why there’s a girl in my kitchen?” he confused.

The fisherman entered the room. “Who are you?” he asked the girl.

“I’m the fish.” The girl said.

The fisherman looked the washbasin and saw nothing in it. “The fish?” he asked incredulous.

“Yes. You didn’t kill me and I’m very thankful. I will return your kindness.” The girl said.

“That’s ok. I didn’t ask any return” the fisherman said.

“But I have to.”The girl insisted.

“Well, I lived alone. I don’t have family. If you want to be my wife, I will be very happy.” The fisherman asked the girl.

The girl smiled and said “I’d love to but you have to promise me that if we have kid you can’t tell him about me.”

And so, the fisherman and the fish girl were married. And then they had a child called Samo. Samo was very naughty. He couldn’t be advisable. He always played and never helped his parents.

One day Samo was asked to deliver lunch to his father. On his way, he met his friends and forgot to deliver his father’s lunch. Samo played with his friends. When he was tired and hungry, he was resting under a tree and ate his father lunch. Meanwhile his father waited him in starve and tired. His father went home and saw Samo played. “Where is my lunch?” he asked.

“Mmm…mm.. I ate it” Samo said afraid.

“Why you ate it?” his father asked.

“Mmm..mm.. I was hungry after playing with my friend” Samo said.

“You were told to deliver my lunch but you didn’t listen.” his father was very furious. “I can’t handle you anymore. You are very naughty. Go away from me. Don’t come home anymore.” His father yelled and evicted Samo from his house.

And this what happened if you can’t control your mouth when you angry. His father said the words that he wouldn’t suppose to say. “You… fish’s son.”

Suddenly, the sky was getting dark. The storm was breaking the ears. The rain felt from the sky like giant hose sprayed water all over the place. And then the water came out from the land and getting harder.

Sumo’s mother was very sad. “I told you don’t tell him about me” she said to her husband. “Now I’m going back to be fish again. Good by” the mother was transformed magically to be gold fish again and disappear through the water. The water was getting higher and drown the village and formed a lake.

Meanwhile, sumo run to the hill and stayed there. The hill then was surrounded by the lake.

Now the lake was known as Toba Lake. Toba came from Tuba word means no mercy. And the hill in the middle called Samosir Island. Samosir means ‘Samo di usir’ or in English : Samo have been evicted.
This is just a legend, there were so many versions of the name’s story. You can’t tell which one is really true. But I heard this version since I was a little girl.